Fluid dampened railway bolster spring

ABSTRACT

A fluid suspension system for railway vehicles having a uniformly varying spring rate to achieve a constant natural frequency in the vertical or bounce mode and to resist lateral or rocking motion of the railway car. The suspension system includes a damper supporting each end of a bolster on the side frame of a railway car truck. Each damper employs resilient material such as synthetic rubber in shear for hysteresis damping and utilizes metering of hydraulic fluid between upper and lower fluid metering chambers to provide hydraulic snubbing action during both compression and expansion of the suspension system to control vertical movement of the vehicle and to resist excessive rolling of the vehicle body. The fluid within the suspension system is maintained under a predetermined preload pressure to help support the load and to dissipate energy as the suspension system expands. Interfitting means between the bolster and the dampers maintain rotational alignment between the truck bolster and side frames.

United States Patent Carle [54] FLUID DAMPENED RAILWAY BOLSTER SPRING[72] Inventor: Ross G. Carle, Houston, Tex.

[73] Assignee: ACF Industries Incorporated, New

York, N.Y.

[22] Filed: Feb. 22, 1971 [21] Appl. No.: 117,810

Related Application Data [63] Continuation of Ser. No. 849,105, Aug. 11,

1969, abandoned.

52 u.s.c1. ..105/197 B, 105/199 cs, 267/3, 267/35 511 1111.121..B61t3/02,B61f5/10,B61f5/l4 Field 61 Search ..105/199 R, 197 A, 197 B,197 R, 105/199 CB; 188/301, 317, 320; 267/35, 63 R, 64 R, 141, 3, 4,118; 280/ 124F; 293 88; 137/4936, 5133,5253;

[5 6] References Cited UNITED STATES PATENTS 3/1940 Kuhn ..267/35 2/1939Richter ..267/35 X 5/1913 Bayley ..188/301 10/1922 Ree ..188/317 8/1926Morinelli 188/320 6/1950 Bateman et al. ..267/64 R 6/ I962 Paulsen..267/63 R 1451 Oct. 31, 1972 3,045,998 7/1962 l-lirst ..105/ 199 R X3,137,466 6/1964 Rasmussen ..280/ 124 F X 3,235,244 2/1966 Hein ..293/88X FOREIGN PATENTS OR APPLICATIONS 620,144 3/ 1949 Great Britain..267/141 Primary Examiner-Drayton E. Hoffman Assistant Examiner-HowardBeltran Attorney-James L. Jackson [5 7] ABSTRACT A fluid suspensionsystem for railway vehicles having a uniformly varying spring rate toachieve a constant natural frequency in the vertical or bounce mode andto resist lateral or rocking motion of the railway car. The suspensionsystem includes a damper supporting each end of a bolster on the sideframe of a railway car truck. Each damper employs resilient materialsuch as synthetic rubber in shear for hysteresis damping and utilizesmetering of hydraulic fluid between upper and lower fluid meteringchambers to provide hydraulic snubbing action during both compressionand expansion of the suspension system to control vertical movement ofthe vehicle and to resist excessive rolling of the vehicle body. Thefluid within the suspension system is maintained under a predeterminedpreload pressure to help support the load and to dissipate energy as thesuspension system expands. Interfitting means between the bolster andthe dampers maintain rotational alignment between the truck bolster andside frames.

4 Claims, 5 Drawing Figures PNENTEDIIBI 31 m2 SHEET 1. 0F 2 FIG. 7

Ross 6. Carla INVENTOR W FIG. 3

A TTORNE Y PATENTED on a 1 m2 SHEET 2 OF 2 Ross 6. Ca

IN VE N TOR ATTORNEY FIG. 4

FLUID DAWENED RAILWAY BOLSTER SPRING This application is a continuationof my copending application Ser. No. 849,105, filed Aug. 11, 1969, nowabandoned.

BACKGROUND OF THE INVENTION This invention relates generally to railwayvehicles and more particularly to an improved resilient suspensionsystem for freight cars. Existing railway cars are almost exclusivelyprovided with metallic coil springs to achieve cushioning and utilizesupplemental friction (coulomb) damping elements for the purpose ofeliminating excessive vertical oscillation at critical velocities. Thecombination of coulomb damping and metallic spring cushioning has beenfound to provide an acceptable ride control in the vertical or bouncemode, but such suspension systems have not been satisfactory in thedevelopment of resistance to lateral motion and rocking motion for somecars with certain configurations resulting in high centers of gravityand certain other parameters.

The metallic coil springs of present railway cars have a constant springrate that results in changing natural frequencies of the railway car asthe railway car loads are changed. It is desirable to provide a varyingspring rate that allows the natural frequency of the railway car toremain unchanged even though the load within the car is changed.

It has been found that the friction damping systems of present railwaycars do not dissipate a sufficient amount of energy to achieve effectivedamping of excessive car body roll and lateral motion which occurs inrailway cars and especially in those cars having relatively high centersof gravity. It is desirable for a railway car suspension system toprovide sufficient damping to prevent excessive car body roll and theaccompanying lateral forces.

The metal coil springs presently employed have little resistance tolateral motion and in present railway vehicles, therefore, lateralforces are generally absorbed mechanically by lugs or gibs castintegrally into the cartruck side frames and bolsters and which interfitto allow limited lateral motion. Lateral loads are known to contributeto car, wheel, and truck component wear.

Accordingly, a primary object of this invention contemplates theprovision of a novel suspension system for railway vehicles that iscapable of providing cushioning and damping in both the vertical orbounce mode and the lateral and rocking mode.

It is a further object of this invention to provide a novel railway carsuspension system provided with spring means having a variable springrate which effectively enables the natural frequency to remain constantas the railway car loads are changed.

It is an even further object of this invention to pro vide a novelrailway suspension system having a cushioning ability that may be variedas desired by changing the gas pressure within the suspension system.

Among the several objects of this invention is contemplated theprovision of a novel railway vehicle suspension system that structurallyinterfits with the railway car truck and bolster geometry in such manneras to allow controlled lateral motion to reduce car, wheel, and truckcomponent wear.

Another object of this invention involves the provision of a novelrailway car suspension system providing 2 hydraulic damping, thusproviding superior damping ability as compared to coulomb damping.

It is an even further object of this invention to provide a novelrailway car suspension system which provides controlled lateral rigidityand damping to allow increased lateral motion while reducing themechanical forces on the bolster and side frame gibs.

A still further object of this invention is to provide a novel railwaycar suspension system with capabilities for restraint of relativerotational motion about a vertical axis through the center of thesuspension means, thereby providing a squaring force to the truckcomponents that will contribute to reduction of wear upon suchcomponents.

Another important object, my invention involves the provision of a novelrailway car suspension system providing both translational androtational alignment means between the truck bolster and side frames,thus improving the truck squaring characteristics and reducing truckcomponent and wheel wear.

Another possible object of this invention involves the provision of anovel railway car suspension system capable of eliminating frictiondamping elements and their attending costs from the truck system.

An important object of this invention is a provision of a novel railwaycar suspension system that is simple in nature, reliable in use, and lowin cost.

Other and further objects, advantages, and features of this inventionwill become apparent to one skilled in the art upon consideration of thewritten specification, the attached claims and the annexed drawings. Theform of this invention, which will now be described in detail,illustrates the general principles of the invention, but it is to beunderstood that this detailed description is not to be taken aslimiting. Such description will be referred by reference characters inthe drawings in which:

FIG. 1 is a partial end view in elevation of a railway car illustratinga railway car truck and car bolster assembly incorporating a suspensionsystem constructed in accordance with the spirit and scope of thepresent invention.

FIG. 2 is a fragmentary end view in elevation of a truck frame and truckbolster assembly having parts thereof broken away and illustrated insection and showing the suspension system of FIG. 1 in section.

FIG. 3 is a plan view taken along lines 33 in FIG. 2 and having the topwall of the inner enclosure broken away to show the fluid meteringsystem of the suspension system.

FIG. 4 is a fragmentary sectional view of the bottom plate structure ofthe inner chamber of FIG. 2 illustrating the fluid metering structure ofthe suspension system in detail.

FIG. 5 is a fragmentary sectional view in elevation of a modifiedembodiment of this invention and illustrating an elastomeric springprovided with vertical reinforcing structural elements.

With reference now to the drawings for a better understanding of thisinvention, in FIG. 1 a railway car is illustrated generally at 10. Therailway car 10 includes a car bolster 12 that is pivotally supported ona railway car truck bolster 14 extending parallel to the car bolster 12.Each extremity of the bolster 14 is received within an opening providedtherefor in a truck side frame 16 and is supported for vertical movementby a suspension system or damper indicated generally at 18. An axle 20is provided for each set of railway car wheels 22 and is journalled inbearings carried within the truck side frame 16. Side bearings 24 and 26are fixed to the bolster l4 and engage bearing stops 28 and 30 to limitrocking motion of the railway car body relative to the truck bolster 14.

With reference now to FIG. 2, the suspension system designated generallyat 18 includes an outer enclosure or housing 31 defined by inwardlytapering side walls 32 maintained in sealed assembly with a generallyrectangular bottom wall structure 34 which forms a base. The side walls32 and bottom wall 34 may be welded together as shown or may beconnected in any other suitable manner. The bottom wall 34 is deformedto define recess structure 36 capable of receiving gibs or stopprojections 38 fixed to the surface 40 of the truck frame 16. The gibsor projections 38 effectively prevent lateral shifting and rotaryoscillation of the outer enclosure relative to the truck frame 16 as thesuspension is subjected to operational movements.

The suspension system 18 is also provided with an inner enclosure orhousing structure 42 having generally rectangular top and bottom walls44 and 46, respectively, that are fixed in sealed relationship toinwardly tapering side walls 48. Mechanical connection between the topwalls, bottom walls, and side walls of the inner enclosure may beprovided by welding or by any other suitable method of connection asdesired. The inner enclosure 42 is disposed substantially concentricallywithin the outer enclosure 31 and the inwardly tapering side walls ofthe inner enclosure are disposed in substantially parallel relationshipwith the inwardly tapering side walls 32 of the outer enclosure.

A generally rectangular mass of elastomeric material 50 that may becomposed of any one of a number of suitable natural rubber, syntheticrubber, or plastic materials is bonded to the outer surface of thetapering walls 48 of the inner enclosure and bonded to the inner surfaceof the tapering walls 32 of the outer enclosure. The elastomeric mass50, therefore, supports the inner enclosure in substantially concentricrelation within the outer enclosure 31. The resilient material serves asan elastomeric spring and is placed in shear as the outer enclosure andinner enclosure are forced toward one another by forces applied throughthe truck frame 16 and bolster structure 14. The mass of elastomericmaterial 50 is also placed in compression as the inner enclosure 42 ismoved laterally toward either of the tapered walls 32 of the outerenclosure under the application of lateral forces from the bolster 14 ortruck frame 16.

Translational and rotational alignment of the inner enclosure 42relative to the truck bolster 14 is maintained by a plurality of gibs orprojections 43 that are connected to or formed integrally with the truckbolster and which are received within depressions formed in the upperportion of the inner enclosure.

The generally rectangular mass of elastomeric material also cooperateswith the inner enclosure 42 and outer enclosure 31 to define a lowerfluid chamber 52 that is separated from an upper fluid chamber 54defined by the inner enclosure 42 by the bottom wall 46 of the innerenclosure. The bottom wall 46 serves as a partition or orifice plate andis provided with a plurality of fixed metering orifices 56 whichestablish fluid communication between the upper and lower fluidchambers. A liquid substance that might be hydraulic fluid or any othersuitable liquid is placed within the chambers through a filling opening58 that is normally maintained closed by a filler plug 60. In theuncompressed condition of the suspension system, the liquid completelyfills the lower fluid chamber and fills the upper fluid chamber to thelevel indicated in FIG. 2. Obviously, the level of liquid within theupper and lower fluid chambers may be varied as desired within thespirit and scope of the present invention. As compressive forces areapplied to the suspension system 18, these forces will be resisted bythe resiliency in shear of the elastomeric spring and by the metering ofliquid from the lower fluid chamber to the upper fluid chamber.Compressive forces are also resisted by a preload pressure developed bya compressive medium, such as air or nitrogen gas disposed in the upperfluid chamber 54. The preload pressure may be controlled as desiredthrough an inflation valve 61 connected, such as by threading, to anupper portion of the inner enclosure 42 which extends upwardly aboveside walls 32 of outer enclosure 31.

During dynamic action of the vertical oscillations of the bolster uponthe suspension system, hydraulic fluid is metered through the fixedmetering orifices 56 which are so sized as to efiectively damp suchvertical oscillations and to restrict the vertical oscillations to anacceptable level, especially at critical velocities. During periods ofmaximum car body roll, the relative velocity of closure or compressionof the suspension system is several times greater than the velocitydeveloped during vertical oscillation or bounce. In order to eliminateexcessive pressures during maximum car body roll, the suspension systemis provided with a normally closed compression metering valves 62illustrated in greater detail in FIG. 4. The metering valve 62 may bewelded to the bottom plate 46 of the inner enclosure 42 as illustratedor may be connected by threading or by any other acceptable means ofconnection. Metering valve 62 comprises a generally cylindrical housing64 having upper and lower closures 66 and 68, respectively, threadedlyor otherwise connected thereto.

A metering orifice 70 is formed in the lower closure 68. The closure 66and the valve housing 64 are provided with apertures 72 and 74,respectively, to allow relatively free passage of fluid therethrough.Within check valve housing 64 is provided a check valve member 76 thatis biased by a compression spring 78 to a position closing the meteringorifice 70. The check valve 76 will open upon reaching a predeterminedpressure difierential between the upper and lower fluid chambersdetermined by the degree of compression of the spring 78. The openingpressure of the check valve 76 may be varied by substitution of thecompression spring or by adjusting the thickness of the closure 66. Thepurpose of the normally closed metering valve 62 is to increase theeffective metering aperture dimension in response to predeterminedincrease and pressure differential to achieve effective damping withoutdeveloping excessive pressure differentials.

At the right portion of FIG. 4 is disposed an expansion metering valveillustrated generally at 80 having a closure 82 connected at the upperextremity of a generally cylindrical valve housing 84. The closure 82 isprovided with a metering orifice 86 that is normally closed by a checkvalve 88 biased to its closed position by a compression spring 90. Alower closure member 92 is connected to the housing in any desiredmanner and serves primarily to support the compression spring 90. Theclosure 92 is also provided with an orifice 94 through which fluid flowsfreely upon opening of the check valve 88.

It is seen, therefore, that upon compression of the suspension systemthe metering valve 62 will be moved to its open condition upon reachinga predetermined pressure differential between the upper and lowerchambers. Upon expansion of the suspension system, the metering valve 62will remain closed and upon reaching maximum allowable pressuredifferential the expansion check valve 80 will open to increase theeffective orifice dimension between the upper and lower chambers. Themetering valves effectively enhance the varying spring rate of thesuspension system.

With reference to FIG. 5, illustrating a modified embodiment of thisinvention, an inner closure 96 and an outer closure 98 are shown to beconstructed essentially identical with respect to the correspondingenclosures 42 and 31, respectively, in FIG. 2. A mass of elastomericmaterial 100 is bonded to the outer walls of the inner enclosure 96 andto the inner walls of the outer enclosure 98 in similar manner asdescribed above in connection with FIG. 2. At least one and preferably aplurality of reinforcing members are molded within the elastomeric massand are disposed in generally parallel relationship with the walls ofthe inner and outer enclosures. The reinforcing members 102 and 104 maybe simple plate-like metal structures provided on two sides of thegenerally rectangular resilient mass 100 or they may be rectangularreinforcing members extending throughout the mass 100 of resilientmaterial. The strengthening members 102 and 104 effectively limitcompression of the resilient mass 100 to provide lateral stiffnesswithout materially changing the resiliency of the elastomeric mass inshear. The configuration of the elastomeric mass, therefore, may bealtered in accordance with the design of a railway car to which it isapplicable in order to achieve different cushioning characteristics.

Under normal operation, the suspension system 18, as illustrated in FIG.2, upon being compressed will cause liquid to be metered from the lowerfluid chamber 52 to the upper fluid chamber 54 through the fixednormally opened metering orifices 56. Resistance to compressive forcesapplied to the suspension system are controlled by the elastomeric mass50, which is placed in shear. Compression of the suspension system isalso resisted by the pressurized compressible medium disposed within theupper fluid chamber 54 and, of course, by the resistance offered by themetering orifices 56 as the suspension system is compressed. Asdescribed above, in the event the rocking motion or vertical oscillationshould produce velocities sufficiently high to cause high pressuredifferential to be developed between the lower fluid chamber and theupper fluid chamber, the metering valve 62 will be forced to its openedposition, thereby adding the dimension of the metering orifice 70 to theeffective metering orifice dimension of the suspension system. Undernormal expansion movement causing the outer enclosure to move away fromthe inner enclosure, the compressive medium within the upper chamber 54and the action of the elastomeric spring 50 will tend to accelerate theexpansion movement. Such acceleration is controlled normally by themetering orifices 56 which will meter fluid from the upper fluid chamberinto the lower fluid chamber 52 and provide resistance to expansion. Inthe event sufficient pressure differential occurs between the upper andlower fluid chambers, the expansion metering valve will open therebyadding the dimension of the metering orifice 86 to the effectivemetering orifice dimension of the suspension system. Damping iseffectively achieved not only during compression of the suspensionsystem, but also during expansion thereof.

In view of the foregoing, it is quite clear that I have provided a novelsuspension system for railway vehicles that is capable of providingcushioning and damping in both the vertical or bounce mode and thelateral or rocking mode. Through the novel design of my suspensionsystem, it is possible to achieve a variable spring rate whicheffectively prevents the changing of resonant frequencies as railway carloads are varied. Railway car truck and wheel component wear iseffectively maintained at a minimum level because the suspension systemof my invention limits lateral forces to an acceptable level. In theevent the particular railway car to which the unit is to be assembled issubject to severe lateral velocities, such velocities can be effectivelycontrolled through the implementation of additional elastomeric springstiffeners that control compressibility without adversely affecting theresiliency of the elastomeric spring in shear. My invention effectivelyachieves superior damping ability even though coulomb or frictiondamping may not be utilized. The structure of my invention effectivelyprovides both translational and rotational alignment between the truckbolster and side frame thereby improving the truck squaringcharacteristics of the railway car so that truck component and wheelwear is reduced. The above-described invention, therefore, is quitecapable of accomplishing all of the objects and advantages hereinaboveset forth together with other objects and advantages that are inherentfrom the description of the apparatus itself.

Having thus described my invention, what is claimed to be new and whatis desired to be secured by letters patent is:

1. In a railway car truck having a pair of side frames with openingstherein receiving the ends of a truck bolster; a damper positioned inthe opening of each side frame for supporting the bolster thereon eachdamper comprising, an outer enclosed housing mounted in supportingengagement on the associated side frame and having a circumferentialside wall, an inner enclosed housing disposed in substantiallyconcentric relation to said outer housing and having a circumferentialside wall with an upper portion thereof extending upwardly beyond theside wall of said outer housing, and a top horizontal wall over thecircumferential side wall of the inner housing having an upper surfacein contact with an adjacent lower surface of the bolster, a mass ofelastomeric material disposed between and bonded to the walls of theinner and outer housings and cooperating with the inner and outerhousings to define a lower fluid chamber, said inner housing defining anupper fluid chamber with a gaseous fluid therein and having a bottomwall defining a partition between said upper and lower fluid chambers,said partition having at least one normally closed metering valve beingoperable to open at a predetermined pressure differential between theupper and lower chambers to permit the flow of fluid therebetween, and agas inlet valve in the upper portion of said side wall of the innerhousing beneath the top horizontal wall in direct fluid communicationwith said upper fluid chamber to preload said upper fluid chamber to apredetermined gaseous pressure, said gas inlet valve being positioned atan elevation above the side wall of said outer housing thereby to beeasily accessible.

2. In a railway car truck, a pair of side frames with openings therein,a bolster having ends fitting within the openings in said side frames, adamper positioned in the opening of each side frame for supporting thebolster thereon and comprising, an outer housing mounted in supportingengagement on the associated side frame and having a circumferentialside wall, an inner enclosed housing disposed in substantiallyconcentric relation to said outer housing and having a circumferentialside wall with an upper portion thereof extending upwardly beyond theside wall of said outer housing, and a top horizontal wall over thecircumferential side wall of the inner housing having an upper surfacein contact with an adjacent lower surface of the bolster, a mass ofelastomeric material disposed between and bonded to the walls of theinner and outer housings and cooperating with the inner and outerhousings to define a lower fluid chamber, said inner housing defining anupper fluid chamber with a gaseous fluid therein and having a bottomwall defining a partition between said upper and lower fluid chambers,said partition having at least one normally closed metering valve beingoperable to open at a predetermined pressure differential between theupper and lower chambers to permit the flow of fluid therebetween, andinterfitting means on the lower surface of said bolster and on theadjacent upper surface of each of the inner housings cooperating tomaintain translational and rotational alignment of the inner housingswith the bolster.

3. In a railway car truck as set forth in claim 2, said interfittingmeans comprising projections extending downwardly from the underside ofsaid bolster and depressions in said inner housings receiving saidprojections.

4. In a railway car truck as set forth in claim 2, a gas inlet valve inthe side wall of each inner housing beneath the top horizontal wall indirect fluid communication with said upper fluid chamber to preload saidupper fluid chamber to a predetermined gaseous pressure, said gas inletvalve being positioned at an elevation above the side wall of said outerhousing thereby to be easily accessible.

1. In a railway car truck having a pair of side frames with openingstherein receiving the ends of a truck bolster; a damper positioned inthe opening of each side frame for supporting the bolster thereon eachdamper comprising, an outer enclosed housing mounted in supportingengagement on the associated side frame and having a circumferentialside wall, an inner enclosed housing disposed in substantiallyconcentric relation to said outer housing and having a circumferentialside wall with an upper portion thereof extending upwardly beyond theside wall of said outer housing, and a top horizontal wall over thecircumferential side wall of the inner housing having an upper surfacein contact with an adjacent lower surface of the bolster, a mass ofelastomeric material disposed between and bonded to the walls of theinner and outer housings and cooperating with the inner and outerhousings to define a lower fluid chamber, said inner housing defining anupper fluid chamber with a gaseous fluid therein and having a bottomwall defining a partition between said upper and lower fluid chambers,said partition having at least one normally closed metering valve beingoperable to open at a predetermined pressure differential between theupper and lower chambers to permit the flow of fluid therebetween, and agas inlet valve in the upper portion of said side wall of the innerhousing beneath the top horizontal wall in direct fluid communicationwith said upper fluid chamber to preload said upper fluid chamber to apredetermined gaseous pressure, said gas inlet valve being positioned atan elevation above the side wall of said outer housing thereby to beeasily accessible.
 2. In a railway car truck, a pair of side frames withopenings therein, a bolster having ends fitting within the openings insaid side frames, a damper positioned in the opening of each side framefor supporting the bolster thereon and comprising, an outer housingmounted in supporting engagement on the associated side frame and havinga circumferential side wall, an inner enclosed housing disposed insubstantially concentric relation to said outer housing and having acircumferential side wall with an upper portion thereof extendingupwardly beyond the side wall of said outer housing, and a tophorizontal wall over the circumferential side wall of the inner housinghaving an upper surface in contact with an adjacent lower surface of thebolster, a mass of elastomeric material disposed between and bonded tothe walls of the inner and outer housings and cooperating with the innerand outer housings to define a lower fluid chamber, said inner housingdefining aN upper fluid chamber with a gaseous fluid therein and havinga bottom wall defining a partition between said upper and lower fluidchambers, said partition having at least one normally closed meteringvalve being operable to open at a predetermined pressure differentialbetween the upper and lower chambers to permit the flow of fluidtherebetween, and interfitting means on the lower surface of saidbolster and on the adjacent upper surface of each of the inner housingscooperating to maintain translational and rotational alignment of theinner housings with the bolster.
 3. In a railway car truck as set forthin claim 2, said interfitting means comprising projections extendingdownwardly from the underside of said bolster and depressions in saidinner housings receiving said projections.
 4. In a railway car truck asset forth in claim 2, a gas inlet valve in the side wall of each innerhousing beneath the top horizontal wall in direct fluid communicationwith said upper fluid chamber to preload said upper fluid chamber to apredetermined gaseous pressure, said gas inlet valve being positioned atan elevation above the side wall of said outer housing thereby to beeasily accessible.